Processes for the fixation of nitrogen from the atmosphere are well known in industry. As discussed in a review by Jean L. Marx in Science, Vol. 185, pages 132-136, July 12, 1974, ammonia was first synthesized from nitrogen in the atmosphere by the Haber-Bosch process in 1913. With modifications, such as the Claude process invented in 1917, manufacturing of synthetic ammonia has continued up to the present day. Ammonia synthesis by such processes requires the expenditure of large amounts of energy, not only in order to produce the constituent hydrogen of the process but also to develop the high temperature and pressures required for the conversion of nitrogen and hydrogen to ammonia.
In another process, known as the Birkeland-Eyde process for the fixation of nitrogen through the production of NO, air is passed through an electric arc flame which produces an equilibrium concentration of NO in air at the high temperature of the flame. The NO is extracted in a series of cooling, absorption towers. Although the process using electric arcs has largely been discontinued, essentially the same method has been revived in which heating is provided by conventional methods and nitrogen and oxygen are partially converted to NO by passing the heated gases over a platinum catalyst.
Following the introduction of nuclear reactors into technology in the late 1940's, it was realized that intense ionization and heat within a nuclear reactor could be employed for the generation of oxides of nitrogen from air. In 1956, Paul Harteck and Seymour Dondes disclosed in U.S. Pat. No. 2,898,277 a technique for producing oxides of nitrogen by using air flowing at high pressures through a reactor.
Similarly, in U.S. Pat. No. 3,298,920 issued to Marvin R. Gustavson, David R. Sawle and Arthur T. Biehl in 1967, a technique was disclosed for producing nitric acid by using a nuclear reactor. In the technique described by Gustavson et al., a fissionable material, in the form of an aerosol smoke, was mixed with air before circulation within the body of a nuclear reactor. Although the nitrogen-oxygen recombination process was essentially the same as in the Harteck-Dondes process, the advantage claimed for the Gustavson technique was that the gases were exposed to enhanced ionizations from the fission fragments recoiling from the fissionable aerosol. In the case of the Harteck-Dondes process, the major sources of ionization were the less-effective x-ray and gamma-ray electromagnetic radiations and the recoiling and disintegration particles arising from neutron interactions.
The present inventor, using theoretical analyses and digital computers, carried out extensive computations of a large number of possible chemical and ionic reactions between numerous species of neutral and ionized molecules and atoms produced when intense particle radiations ionize air. (See: Preliminary Report on Heating Processes in Intensely Ionized Air, by R. D. Hill, Report 1-93 Coordinated Science Laboratory, University of Illinois, 24 June 1960). In considering the results of these calculations, significant though small yields of the oxides of nitrogen were recognized to be produced by direct irradiation of ambient air with ionizing radiation in a manner similar to irradiation with reactor radiation, as was indicated in the patents just cited.
While such structures and interactions for the fixation of nitrogen using nuclear radiations have been known for some time, it is understandable, as pointed out by David R. Safrony in a recent article in Scientific American, Vol. 231, pages 64-80, Oct. 1974, that the so-called "chemonuclear" techniques have never met with significant usage. This is mainly for two reasons: first, that special nuclear reactor designs are required to ensure that a large proportion of fission-produced fragments interacts directly with the gas mixture (or air), and second, that almost complete decontamination of the gas mixture and nitrogen oxides from the highly radioactive products of uranium fission is required before the technique can be considered in any way radiologically acceptable.